In the coming year, we shall be completing the work in the cat on alterations in resting rate, sensitivity and other dynamic characteristics of Type I horizontal canal brain stem vestibular neutrons after acute and chronic contralateral labyrinthectomy. We shall be doing a combined morphological and physiological study in mammals, trying to relate properties such as spontaneous firing rate, adaptation, time constants of first order vestibular afferents in the cat to specific locations of receptors on the crista. BIBLIOGRAPHIC REFERENCES: Curthoys, I.S., Blanks, R.H.I. and Markham, C.H.: Semi-circular canal radii of curvature (R) in cat, guinea pig and man. J. Morph. 151:1-16, 1977. Curthoys, I.S., Markham, C.H. and Curthoys, E.J.: Semi-circular duct and ampulla dimensions in cat, quinea pig and man. J. Morph. 151:17-34, 1977.